06 LS 3.9 O2 Sensors

[hagence]

I just purchased this LS, It has 102K miles and runs like a dream. But it is throwing a bank 1 below threshold code into my code reader. Not on the dash yet.

With only 102K on it, would the Catalytic converter be bad? or Would it be the O2 Sensor.

I suspect bank 1 is the Passenger Side and if it is a sensor it would be downstream. (after the Cat) Am I right?

Also, are the sensors interchangeable? Upstream and Downstream?

Thanks, any info would be extremely helpful.

Chris

 

[hagence]

I also wanted to say, I found and repaired a vacuum leak on top of the engine, at the very front. Two small plastic vacuum lines that are covered and taped. Could that leak have been throwing a code for bank 1? It was hissing pretty loud till I fixed it.

 

[1LoudLS]

well, these cars are known for having cat killing coil problems if things are not corrected as soon as things start going bad.

 

[hagence]

That's kind of hard to wrap my head around. My Mercury Grand Marquis has 240k has had plenty of potentially cat killing problems over the years. Never a problem with the kitties.how different could they be? I know... and replacing the cats on the LS is on the table. It is nearly the last of my initial problems. Front wheel bearings, brakes all around, belt, idler, and tensioner. ABS issue ironed out. Sensor or cats, some new shoes...
Finally a winshield is in order too.

It's amazing how you can't see that list problems in the picture.

 

[LS4me]

That's kind of hard to wrap my head around. My Mercury Grand Marquis has 240k has had plenty of potentially cat killing problems over the years. Never a problem with the kitties.....

That's because the coils fail marginally causing misfires that can last for many thousands of miles before they fail enough to set a code. By that time enough raw fuel has been dumped into the exhaust that it burns-up and destroys the cats.

 

[1LoudLS]

how different could they be

well for starters, very...

those two cars are nothing alike other than the motor is facing the right way, the wheels are round and there are four of them.

 

[joegr]

...how different could they be? ...

The LS is more Jaguar than Ford. Just look it up and see how many repair parts are common between the Grand Marquis and the LS. (You won't need a whole page for the list.)

 

[Telco]

The O2 sensors are not swappable front to back, but they are swappable left to right. Swap the left and right rear O2 sensors. If the problem switches sides, the problem is the sensor. If the problem does not follow, the problem is the cat. If the problem is the cat, replace the COPs and plugs when the cat is replaced.

 

[hagence]

Got stuck working all weekend. My apologies for the delay.
First I appreciate the ton of good info I picked up. Thanks for the replies.

I know there is no comparison between the grand marquis and the ls... but I did expect a little more Ford dependability.

I will be swapping rear sensors today. I will keep you posted with the results. And I will follow up with the forum on the total fix up on this ls.

Thanks.

 

[1LoudLS]

but I did expect a little more Ford dependability.

The LS is more Jaguar than Ford.

the problem is there is isn't enough ford in it... and well British cars are pretty much known to be the exact opposite of reliable! lol

 

[hagence]

Update: I have swapped sensors and reset codes and still coming up p2040 bank 1.

I fixed the vacuum leak and the motor has no current noticable misfires. Next step is to replace the catalytic converters. I can buy both down to the "Y" factory fit for about $400 and have them installed for less than $100.
Waiting for some funds to come in. I will keep you all posted as promised.

Thanks for all the info and support so far!

Chris

 

[joegr]

... Next step is to replace the catalytic converters. ...

Replace all the coils and plugs first, or you will be doing this again soon. (The typical marginal failure of the coils is difficult to impossible to "feel.")

 

[1LoudLS]

Replace all the coils and plugs first, or you will be doing this again soon. (The typical marginal failure of the coils is difficult to impossible to "feel.")

and definitely next to impossible for even the computer to notice

 

[hagence]

Wow. I really appreciate the insight.
So in general, it sounds as if coils should be changed on a regular frequency. Is it ok to buy inexpensive? (Rock Auto) or woud a better spark plug be helpful?

any info can be good. Just trying to do it right.
Thanks

 

[joegr]

In my opinion and experience, OEM coils only. Also the OEM plugs (Motorcraft or NGK) are the best plugs. There's no point is going for better, because the plugs already go 100K miles. Would you really want to leave them in longer than that?

 

[hagence]

Thanks so much for the great input. The Lincoln LS is rolling like a champ. No codes and running great. I had eliminated all the cat damaging issues (mis-fire and vacuum leaks) prior to replacing the catalytic converters. (Changed them both along with the resinator? before the mufflers.) It might just be my own excitement but, it actually feels more powerful. I couldn't have gotten through the issues as smoothly without all the help and info I got here. This LS is a beast! Thanks again.

As soon as skin on my right arm heals up from changing the surpentine belt. All will be well. (Yes, changed the belt without removing the radiator shroud.)

Chris

 

[joegr]

...As soon as skin on my right arm heals up from changing the surpentine belt. All will be well. (Yes, changed the belt without removing the radiator shroud.)

Chris

The effort to remove that "shroud" is not worth it for a belt change. You'd lose some skin removing it anyway.

 

[don-ohio]

Yes, vacuum leaks tell the O2 sensor you're running lean, and the computer richens the mixture.ALSO,if a plug is misfiring,the damage is doubled because the O2 sensor reads the exhaust stream as lean and also richens the mixture.
So like was said, COPs,plugs,and I'm telling you vacuum leaks will mess you up and code you. don-ohio ^)

I also wanted to say, I found and repaired a vacuum leak on top of the engine, at the very front. Two small plastic vacuum lines that are covered and taped. Could that leak have been throwing a code for bank 1? It was hissing pretty loud till I fixed it.